Sound Transit Tukwila Commuter Rail Station Project

Impacts Table

Impact Category 2008 Design (Impacts as Initially Disclosed) December 2010 Design (New Impacts) Ch

Land Use 

Conversion of undeveloped land to station and associated parking; supports development of new and more intensive uses in Tukwila urban center.

Station platforms located where existing station is; parking located where stormwater detention was proposed in 2008; stormwater detention located below parking instead at surface as proposed in 2008 Slightly less land c

Transportation 

Growth in traffic, parking and non-motorized travel demand over time.

Same growth in traffic, parking, and nonmotorized travel demand as 2008 Design. There would be minor differences in roadway and pedestrian access to the station, but the impacts would be substantially the same as those in the EA. The primary access to the station would be through the existing underpass below the UPRR tracks at Longacres Way. 

No change. Howevremain in place, pemovement in the pdifferent. The existWay would remain access to the statitemporary station.

Social and Economic Impacts

No adverse impacts to community cohesion or neighborhood character. Minor benefits to community cohesion due to better accessibility than existing station, and minor economic benefits due to improved mobility and short term effects from spending in the area during construction. Same as 2008 Design No change 

Biological Resources

The 2009 EA discussed the possibility of the UPRR tracks remaining and the potential that wetlands would remain in place and their buffers would be impacted by the parking area for the station if the UPRR tracks were not relocated. 

The only wetland impact from the project is that the buffer of Wetland O would be reduced from 50 feet to 15 feet in width on the east side of thewetland. Mitigation will be provided per City of Tukwila regulations, which require replacement of the wetland (1,470 sf). Mitigation will be provided through wetland mitigation bank credits obtained under an agreement with the City of Renton dated January 11, 2011. In March 2010 the City of Tukwila made the determination that Wetland N is non-jurisdictional and therefore no buffers are required for that wetland.

Impacts to wetlandless than those deS (6,428 sf), which TCRS project descbe completely filled project being consand BNSF, prior to with mitigation proThe redesigned StWetland N (1,042 

place. Of these, onrequirements in thbeing eliminated aenvironmental docWetland O would bapproximately 15 fremaining buffer, awhich the City of Teliminating the wetthrough mitigation Transit.

Water Quality and Hydrology

Temporary erosion and sedimentation impacts 

possible during construction but limited by BMPs; long term water quality controlled by compliance with stormwater treatment requirements, which result in minimal increases in pollutant loadings and temperature impacts to receiving water Same as 2008 Design No change

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Sound Transit Tukwila Commuter Rail Station Project

Impacts Table

Impact Category 2008 Design (Impacts as Initially Disclosed) December 2010 Design (New Impacts) Ch

Vibration and Noise 

Temporary noise impacts during construction, limited to daytime construction hours; slight shiftin location of train stops and starts, and location

of train whistle signal Same as 2008 Design No change.

Air Quality 

Increased traffic accessing the facility would result in small increase in air pollutants in the station area but would not result in violations of standards; growth in use of the facility would reduce impacts regionally. Same as 2008 Design No change 

Historic, Archaeological, and Cultural Resources

The project site and area have a high probability for hunter-fisher-gatherer, ethnographic period historic Indian, and historic period archaeologicalresources, although none are known within the project boundaries. Project plans will include construction monitoring and contingency planning for inadvertent discovery. Same as 2008 Design No change

Visual Quality & Aesthetics

After relocation of tracks by others, conversion of grassy area between two sets of railroad tracks to station with parking, roads, lighting, and landscaping; no scenic vistas, historic resources or other sensitive viewpoints would be affected. Views of the Cascade Mountains from the upper floors of adjacent development would not be affected. 

Similar to 2008 Design, except the platform would be shifted to the north approximately 700 feet, and there would be no tunnel added under the tracks for pedestrians. 

The visual context because the UPRR which would limit varea from west of located further norviews significantly

Geology & Soils (Include seismic hazard as appropriate)

Site is subject to liquefaction in an earthquake; design addresses this through subgrade preparation and earthquake-resistant design for structures. Same as 2008 Design No change

Public Services 

No significant disruption of, or increase in demand for public services, including police and fire services provided by the City of Tukwila, and transit provided by King County and Sound Transit. Same as 2008 Design No change

Utilities 

Most utility lines crossing the site would be protected in place and only minimal interruptions in service would be required. A Metro wastewater pipeline that crosses the site north-south would be relocated to the Western Access Road for greater convenience of access in the future. 

Similar to 2008 Design, except that PSE overhead lines would not be affected, no parking would be built over the SPU water main; and the Metro wastewater pipe crossing north-south 

would not be relocated and would be protected in place.

Impacts would be EA, with minimal dImpacts to Metro wlines and SPU wat

Safety and Security 

No adverse impacts anticipated with measures being developed to ensure safety of passengers, and to ensure seismic stability of structures. Same as 2008 Design No change

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Sound Transit Tukwila Commuter Rail Station Project

Impacts Table

Impact Category 2008 Design (Impacts as Initially Disclosed) December 2010 Design (New Impacts) Ch

Energy

Station would consume resources for construction such as sand, gravel, water and petroleum (for paving). Operation may require small increase in electrical consumption for security lighting. Project enhances transit mobility which reduces regional energy consumption. Same as 2008 Design No change

Hazardous Materials 

No hazardous materials are known to be present on the site. There is risk of undocumented hazardous materials associated with the railroad tracks (creosote or spills). There is also a risk of 

spills during construction. No transport of hazardous materials is proposed. Mitigation includes training construction crews, and reporting and remediating hazardous materials discovered or spilled during construction. Same as 2008 Design No change

Construction 

Construction impacts would include dust and vehicle emissions, equipment noise, potential erosion and sedimentation, risk of inadvertent discovery of hazardous material or cultural resources, a minor increase in traffic, and possible damage to roads during construction. Same as 2008 Design No change

Secondary and Cumulative 

No significant adverse secondary or cumulative impacts are anticipated. The project would be consistent with, and to a degree would catalyze, planned growth in population, employment, and transportation demand for the project area. Impacts to water and wetlands could contribute to cumulative effects from similar development in the area, but current regulations require 

mitigation that will avoid net loss of wetlands, and minimize pollutants reaching fish-bearing waters to the extent feasible. Demand for energy, utilities, and services are expected to grow over time, but there are no known capacity limitations at this time. All other impacts would be similar to impacts expected from other development anticipated for the area and thus could contribute cumulatively to impacts but, assuming compliance with existing regulations, the cumulative impacts are expected to be minimal.

Impacts would be similar to the 2008 design, except that the UPRR relocation project would not occur, leaving in place some wetlands that previously were assumed would be filled and mitigated off-site. 

Impacts would be 2009 environmentthe Strander Projeand leave in place UPRR tracks. The cumulative wetland for relocation of th

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